Typeerror: sequence item 0: expected str instance, list found

Question

Problem:

I was trying to insert data from one of my dictionaries into my database for that I wrote the code:

def all_db_inserts(dbinformation):
    try:
        rows = dbinfo['datarows']

        for row in rows:
            field_names = ",".join(["'{0}'".format(x) for x in row.keys()])
            value_list = row.values()

            for pos, value in enumerate(value_list):
                if isinstance(value, str):
                    value_list[pos] = "'{0}'".format(value)
                elif isinstance(value, datetime):
                    value_list[pos] = "'{0}'".format(value.strftime('%Y-%m-%d'))

            values = ",".join(value_list)

            sql = "INSERT INTO table_foobar ({0}) VALUES ({1})".format(field_names, values)

    except Exception as x:
        print 'BARFED with msg:',x

But I got this error message when I try to run this(using sample data):

TypeError: sequence item 0: expected string, int found

Can anyone help me out?

Answer 1

You are having this error because of the line:

values = ",".join(value_list)

What to do:

You should replace

values = ",".join(value_list)

with

values = ','.join([str(i) for i in value_list])

OR

values = ','.join(str(value_list)[1:-1])

or

values = ','.join(map(str, value_list))

If it is still not working for you let me know about it and fell free to ask me anything.

Happy coding.

Answer 2

Be aware that some values could be Unicode strings and may cause the str to throw a UnicodeEncodeError error.

Solution 1:

In that cause replace the str function by the function Unicode.

Example:

Assume the string libie(Dutch for Libya) represented as the Unicode string u’Libi\xeb’ in python.

print str(u ‘Libi\xeb’)

This will throw an error;

Traceback (most recent call last):

  File "/Users/tomasz/Python/MA-CIW-Scriptie/RecreateTweets.py", line 21, in <module>

    print str(u'Libi\xeb')

UnicodeEncodeError: 'ascii' codec can't encode character u'\xeb' in position 4: ordinal not in range(128)

The following line will throw an error message;

print unicode(u'Libi\xeb') # prints Libië

so replace the line;

values = ','.join([str(i) for i in value_list])

with the following line of code;

values = ','.join([unicode(i) for i in value_list])

This will help to avoid errors.

Solution 2:

Replace the following lines of code;

values = ",".join(value_list)

with the one of the following line;

values = ','.join([str(i) for i in value_list])

OR

values = ','.join(str(value_list)[1:-1])

Solution 3:

The user can also convert the integer data frame into a string first and then do the operations. This can be done by using the following line of code;

df3['nID']=df3['nID'].astype(str)

grp = df3.groupby('userID')['nID'].aggregate(lambda x: '->'.join(tuple(x)))